2019-06-21/DrFogh
2019-09-13 You really do not want to use this since this is an old version of Circular Challenge 6. Play the final level. It is much better.
Did you find this one tough to solve? Probably to tough since you are reading this 🙂
I will not give you the solution but a few hints with a few positions on the way.
NB: This is the second version of the level with an extra wall at H4 by Anian. Don’t bother about my first version. It is to easy and will not be republished.
The first 25 or so moves are quite mandatory and should not give you much trouble.
You need slide the box at H8 to one side or another to get access to the lower half of the level. The illustrated moves in the center are necessary.
On the way doing that you should put a box at H3(or in the vicinity) to get more room for moves in the middle and bottom of the level. 
Passing the barrier in the middel to reach the lower half is also quite straight forward and you will reach a position close to the one above.
Push the marked boxes up to get room for your movements.
You can now solve the left and right branch individually without much trouble.
The tricky part is getting the central 6/8 boxes in the right position. Don’t give up. It is possible of course.
When everything is done in the lover half make the indicated pushes. Push the box at G7 to G10 and finish the top half of the level.